An adaptive framework for spectral-spatial classification based on a combination of pixel-based and object-based scenarios     

Amin Zehtabian  Hassan Ghassemian 《Earth Science Informatics》2017,10(3):357-368

Remotely sensed image analysis using spectral-spatial information plays a key role in modern remote sensing applications. This article presents a new semi-automatic framework for spectral-spatial classification of hyperspectral images. The proposed framework benefits from a combination of pixel-based and object-based classification scenarios in which the main parameters are adaptively tuned. In order to reduce the complexity of the method, an unsupervised band selection technique is used as well. Meanwhile, the wavelet thresholding is applied in order to smooth the selected bands. The classification results after applying the proposed method to well-known standard hyperspectral datasets are better than those of the most of the other state-of-the-art approaches. As an example, the overall classification accuracy achieved by applying the proposed semi-automatic spectral-spatial classification framework to the Salinas dataset is more than 99% for 10% training samples per class. Moreover, the vital parameters are adaptively set in our approach.  相似文献   

Pattern recognition of major asperities using local recurrence time in Alborz Mountains, Northern Iran     

Khalil Motaghi  Khaled Hessami  Mohammad Tatar 《Journal of Seismology》2010,14(4):787-802

In this study, seismic data recorded during the period 01/01/1996 to 09/01/2009 has been used to evaluate the seismic hazard potential along the Alborz region, Northern Iran. The technique of mapping local recurrence time, T _L, is used to map major asperities, which are considered as the areas with maximum hazard. We calculated T _L from a and b values which are in turn derived from the frequency–magnitude relation constants within a radius of 30 km about every corner point of a 10-km spacing grid. Since b value is inversely related to applied stress, the areas with lowest b values and/or shortest T _L are interpreted to locate the asperities or the areas of maximum seismic hazard. To test this method, we computed T _L map using seismic catalogues before and after the 2004 Baladeh earthquake of M _w 6.2. The local recurrence time map before the earthquake shows anomalously short T _L in the epicentral region of the Baladeh earthquake a decade before its occurrence. The T _L map after the earthquake indicates that this large event has redistributed the applied stress in the Alborz region. The microseismicity of the region after the Baladeh earthquake, however, suggests that there are two anomalies in T _L map positioned in Alborz. The places where these anomalies are observed can be considered as the areas with maximum seismic hazard for future large earthquake in the Alborz region.  相似文献   

Thank you to 2022 Ocean Dynamics reviewers     

Ezer  Tal  Carniel  Sandro  Amin  Chabchoub  de Camargo  Ricardo  Estrada-Allis  Sheila N.  Gao  Guoping  Greatbatch  Richard J.  Lermusiaux  Pierre F. J.  Liu  Zhiyu  Miyazawa  Yasumasa  Forster  Alejandro Orfila  Panickal  Swapna  Phillips  Helen  Pinones  Andrea  Stanev  Emil  Volker  Christoph  Xu  Fanghua  Young  Emma 《Ocean Dynamics》2023,73(1):35-38

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Fault seal prediction of seismic-scale normal faults in porous sandstone: A case study from the eastern Gulf of Suez rift,Egypt     

Christian Tueckmantel  Quentin J. Fisher  Rob J. Knipe  Henry Lickorish  Samir M. Khalil 《Marine and Petroleum Geology》2010

A study of normal faults in the Nubian Sandstone Sequence, from the eastern Gulf of Suez rift, has been conducted to investigate the relationship between the microstructure and petrophysical properties of cataclasites developed along seismic-scale faults (slip-surface cataclasites) and smaller displacement faults (deformation bands) found in their damage zones. The results help to quantify the uncertainty associated with predicting the fluid flow behaviour of seismic-scale faults by analysing small faults recovered from core, a common procedure in the petroleum industry. The microstructure of the cataclasites was analysed as well as their single-phase permeability and threshold pressure. Faulting occurred at a maximum burial depth of ∼1.2 km. The permeability of deformation band and slip-surface cataclasites varies over ∼1.5 orders of magnitude for a given fault. Our results suggest that the lowest measured deformation band permeabilities provide a good estimate for the arithmetic-mean permeability of the major slip-surface cataclasites. This is because the cataclastic permeability reduction is mostly established early in the deformation history. Stress at the time of faulting rather than final strain appears to be the critical factor determining fault rock permeability. For viable predictions it is important that the slip-surface cataclasites and deformation bands originate from the same host. On the other hand, a higher uncertainty is associated with threshold pressure predictions, as the arithmetic-mean slip-surface cataclasite threshold pressure exceeds the highest measured deformation band threshold pressure by at least a factor of 4.  相似文献   

广东清远早、晚稻稻田甲烷排放的观测研究   总被引：1，自引：0，他引：1  

许黎  任万辉  杨宁  王天龙  刘锦銮  M A K Khalil  R A Rasmussen  M J Shearer 《气象》2007,33(3):19-27

分析了2003、2004年广东省清远市郊区早、晚稻稻田甲烷（CH4）的排放通量,结果表明：广东清远早、晚稻稻田CH4排放通量的几何平均值2003年为4,38mg·m^-2·h^-1和6．09mg·m^-2·h^-1;2004年为5．17mg·m^-2·h^-1和8．3mg·m^-2·h^-1,土壤有机质含量是造成2003和2004年CH4排放差异的原因之一。水稻品种的不同,CH4排放通量也有所不同,实验表明,水稻品种“七丝尖”的排放通量比品种“金优99”高1．08mg·m^-2·h^-1,产量却只有64％。此外,与相关的测量结果进行初步比较。  相似文献   

Decrease in the clear air transmission at Helwan Observatory site     

J. S. Mikhail  B. B. Baghos  M. Y. Tawadrous  Y. E. Helali  H. Awad  KH. I. Khalil  M. El-Saftawe  M. Ibrahim 《Earth, Moon, and Planets》1995,70(1-3):143-149

Clear air atmospheric transparency of eight nights at Helwan Observatory site during autumn period of 1987 have been determined using the yellow filter GG5. The prevailing atmospheric transmission extends to 58%. A comparison with previous values obtained with the same filter and site during autumn period of 1963 shows a considerable decrease at the present years in the clear air transmission of the site of Helwan. This can be attributed to the aerosol pollution of the site caused mainly by the increase of the industrial centers at Helwan Zone. Clear air atmospheric transparency values at the beginning of winter season and at spring season are also given.  相似文献   

Time dependent chemical study of contracting interstellar clouds. I. Abundances of nitrogen- and carbon-bearing molecules     

M. Y. Amin  M. S. El Nawawy  B. G. Ateya  A. Aiad 《Earth, Moon, and Planets》1995,69(2):95-112

We have constructed a reaction system containing the chemical families of H, C, O, N, S, Si, Cl, metals (Me) and grains. A total of 104 species have been included and a network of 557 reactions has been studied. The chemical kinetic equations were integrated as a function of time by using gear program. The chemical reaction system was followed at low, intermediate and high cloud densities i.e. from 10–10⁷ particles cm^-3. The calculated fractional abundances of N₂, CN, HCN, and CH which are in good agreement with the results of observations and with those of previous theoretical studies.  相似文献   

Floods in Bangladesh: A question of disciplining the rivers     

Gazi Md. Khalil 《Natural Hazards》1990,3(4):379-401

Bangladesh has been experiencing floods more frequently than ever before. Since 1947, she has been hit by extremely devastating floods in 1954, 1955, 1956, 1962, 1963, 1966, 1968, 1969, 1970, 1971, 1974, 1976, 1984, 1987, and 1988. Each year's highest flood record and damage costs have been broken by that of the subsequent year. All means of communication become paralysed. People lose food grains, domestic animals, homesteads, and lives. They remain marooned without food and drinking water until relief arrives. Despite huge spending on flood control, the intensity of the floods has been increasing. Therefore, speculation is naturally rife about the causes.The aim of this paper is to identify the factors which contribute to these devastating floods, and then to recommend an appropriate strategy for effective flood control. The geography, geology, and hydrology of Bangladesh are briefly discussed. The whole of the country is a huge river basin criss-crossed by as many as seven hundred rivers, tributaries, and distributaries, having a total length of 22 155 km.The river-beds are rendered shallow by heavy deposits of alluvial earth each year and tend easily to cause inundations. The quantum of silt carried by the river systems into Bangladesh is estimated to be 2.4 × 10⁹ tonnes/yr.Disciplining the rivers means keeping the rivers navigable all year round, removing excessive deposits of silt where they threaten to block a channel, preventing widening by erosion, contracting the width where the river is excessively wide, and last but not least, preventing construction whose eventual impact might prove harmful.Natural disasters do not respect political frontiers, nothing can stop them, but their adverse impact could be minimised. The author emphasises the need for employing the abundant cheap manpower, local materials, and indigenous technology for flood control projects.  相似文献   

Integrating the multi-label land-use concept and cellular automata with the artificial neural network-based Land Transformation Model: an integrated ML-CA-LTM modeling framework     

Hichem Omrani  Amin Tayyebi  Bryan Pijanowski 《地理信息系统科学与遥感》2017,54(3):283-304

Cellular automata (CA) and artificial neural networks (ANNs) have been used by researchers over the last three decades to simulate land-use change (LUC). While conventional CA and ANN models assign a cell to only one land-use class, in reality, a cell may belong to several land-use classes simultaneously. The recently developed multi-label (ML) concept overcomes this limitation in land change science. Although the ML concept is a new paradigm with nonexclusive classes and has shown considerable merit in several applications, few studies in land change science have applied it. In addition, determining transition rules in conventional CA is difficult when the number of drivers is large. Since CA has been shown as a potential model to consider neighborhood effects and ANN has been shown effective in determining CA transition rules, we integrated both CA with an ANN model to overcome limitations of each tool. In this study, we specifically extended the ANN-based Land Transformation Model (LTM) with both a CA-based model and the ML concept to create an integrated ML-CA-LTM modeling framework. We also compared, using standard evaluation measures, differences between the proposed integrated model with a conventional CA-based LTM model (called the ml-CA-LTM). Parameterization was made using a learning and testing procedure common in machine learning. Results showed that the modified LUC model, ML-CA-LTM, produced consistently better goodness of fit calibration values compared to the ml-CA-LTM. The outcome of this modified model can be used by managers and decision makers for improved urban planning.  相似文献   

Mass Estimation in the Globular Cluster M4     

M.Y. Amin  M. Rassem  M. Marie 《Astrophysics and Space Science》1997,250(1):137-146

Using the kinematical data we try to solve the Jeans equation to provide mass estimation of the globular cluster M4. The proper motion data provides two independent velocity dispersion profiles which we need in this estimation. Moreover, we have calculated the density distribution function and checked the anisotropy of the velocity dispersion. The comparison of the dynamical mass with the estimation stellar mass for M4 gives the best estimation of the mass inside a spherical shell centered on the cluster, with a radius corresponding to 840 arcsec on the sky, as 4-5× 10⁴ M . This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献